Flood Data Q3 is derived from the Flood Insurance Rate Maps (FIRMs) published by the Federal Emergency Management Agency (FEMA) mapped at 1:24000 scale. The file is georeferenced to the earth's surface using the Universal Transverse Mercator (UTM) projection and a zonal coordinate system (units in meters). Specifications for the horizontal control of Q3 Flood Data files are consistent with those required for mapping at a scale of 1:24000.  This data product preceded the current Digital Flood Insurance Rate Maps (DFIRMs).  For more information on the transition from the older Q3 to current DFIRM products visit https://www.fema.gov/media-library/assets/documents/3846